The present general inventive concept relates to semiconductor devices and, more particularly, to vertical type memory devices.
In order to achieve superior performance and lower cost, there is an ongoing need for increasing the density of a semiconductor device. Especially, the density of the semiconductor device is an important determinant for pricing products. Since the density of a conventional two-dimensional semiconductor memory device is mainly decided by an area occupied by a unit memory cell, the density is significantly affected by the level of a fine patterning technology. However, ultra-high cost equipment is required to achieve such fine patterns. Hence, there is still a limitation in increasing the density of the two-dimensional semiconductor memory device.